Conventionally, as disclosed in the Patent Literature 1, an enclosing and sealing machine to take in a printed document from a tray type supply unit, fold the document, and perform enclosing and sealing is known. Since this enclosing and sealing machine directly encloses a document from a printer into an envelope and seals the envelope, it is appropriate to formation of a sealed letter requiring confidentiality of content such as contents-certified mail.
However, since the above-described enclosing and sealing machine lacks a mechanism used in combination with a printer, the confidentiality of an enclosed document is not complete. Then, an enclosing and sealing machine available in combination with a printer or a multi-function peripheral to attain high confidentiality is proposed as disclosed in the following Patent Literature 2. This enclosing and sealing machine has taking-in means for taking in a printed sheet discharged from print means, folding means for folding the sheet taken in by the taking-in means, enclosing means for enclosing the sheet folded by the folding means, by one to plural sheets as a unit, into an envelope, sealing means for sealing the paper-enclosed envelope, and conveying means for conveying the sheet among the respective means. Further, the taking-in means is attachable/removable to/from a paper discharge opening of the print means. Since this enclosing and sealing apparatus is used in combination with a printer or a multi-function peripheral, the process from printing on a sheet to enclosing and sealing can be performed at once.